1. Field of the Invention
The present invention relates to an information distribution system such as a video-on-demand (VOD) system. More particularly, the present invention relates to a method and apparatus providing in-band messaging to functional elements and/or subscribers within an information distribution system.
2. Description of the Background Art
VOD systems providing content encoded according to the various Moving Pictures Experts Group (MPEG) standards are known. For example, a first standard known as MPEG-1 refers to ISO/IEC standards 11172, which is incorporated herein by reference in its entirety. A second standard known as MPEG-2 refers to ISO/IEC standards 13818, which is incorporated herein by reference in its entirety. Additionally, a compressed digital video system is described in the Advanced Television Systems Committee (ATSC) digital television standard document A/53, incorporated herein by reference.
Video on demand systems typically utilize relatively high speed communications channels (also known as “in-band” channels) to provide video content and other bandwidth-intensive information to subscribers or users within the system. Additionally, communications between various functional elements within the system and/or between the system and subscribers may be accomplished via relatively low bandwidth communications channels. These relatively low speed channels (also known as “out-of-band” channels) provide an effective means of routing command messages, control messages and other non-content data within the system. An exemplary out-of-band (OOB) communications channel comprises a non-Gigabit Ethernet network, while an exemplary in-band (IB) channel comprises a high speed data channel such as a satellite link, ASTC cable or terrestrial broadcast link and the like.
Unfortunately, it may be expensive or difficult to route appropriate out-of-band communication channel links to all of the portions of an interactive information distribution system utilizing such links. For example, a functional element serving to perform transport or transmission processing of information at a physically remote site such as a remote satellite up-link, remote cable head end or hub and the like. In such a situation, the remote functional element may require only moderate amounts of control data. Thus, the cost in terms of installation and under utilization of bandwidth capacity is not clearly justified in providing OOB communication channels.
Therefore, it is seen to be desirable to include command and control information within an in-band channel(s), such that command and control information may be provided to functional elements or subscribers receiving and/or processing the in-band channel. Moreover, it is deemed to be desirable to provide such in-band control or messaging information in a manner avoiding interference with content or other streams normally provided by the in-band communication channel.